Drafting pen with magnetically reciprocated cleaning wire



E. BoK 3,535,048

DRAFTING PEN WITH MAGNETICALLY RECIPROCATED CLEANVING WIRE Oct. 20, 1970 Filed Oct. 24, 1968 d f//J Mm a q i M VWM l 2 H Q g |llx Uv Il v i ,M Z w nx aff/falli a f, fw Il. a l W.

INVENTOR United States Patent O 3,535,048 DRAFTING PEN WITH MAGNETICALLY RECIPROCATED CLEANING WIRE Edward Bok, Falls Church, Va., assignor to Dike, Inc.,

Washington, D.C., a corporation of the District of Columbia Filed Oct. 24, 1968, Ser. No. 770,178 Int. Cl. B43k 1/10 U.S. Cl. 401-258 5 Claims ABSTRACT OF THE DISCLOSURE Stylographic drafting pens of the type embodying au ink reservoir and scriber channel with a cleaning wire extending from the reservoir through the scriber channel, particularly magnetic means attached to the cleaning wire so as to reciprocate longitudinally the cleaning wire within the scribing channel.

CROSS-REFERENCE TO RELATED APPLICATIONS Drafting pen with vent valve Pat. No. 3,463,598; Drafting pen Ser. No. 760,923, led Sept. 19, 1968.

Applicants earlier tiled Drafting Pen application Ser. No. 760,923, filed Sept. 19, 1968 disclosed the use of a reciprocable cleaning wire for clearing the ink capillary passage or scriber channel. A knob extended through the pen barrel, surrounding the ink reservoir so as to manually actuate the cleaning wire. Also, in applicants Drafting Pen With Vent Valve, Pat. No. 3,463,598, liled Sept. 11, 1968 applicant disclosed the use of an ink reservoir venting valve operable simultaneously with the cleaning wire, so as to assist in ink tlow, as the scribing channel is cleared of dried ink.

BACKGROUND OF THE INVENTION (l) Field of the invention Contemporary drafting pens include for the most part a cylindrical hard metal tip and a clearing needle extending from the reservoir axially of the tip. The needle usually has a weight seated in the reservoir, so that a jerking movement of the pen will unseat the weight and actually reciprocate the needle within the ink-ilowing capillary passage which extends from the reservoir through the cylindrical pen tip. This reciprocation of the needle clears the passage of crystallized ink permitting a normal ink flow during drawing. According to such pen structures the clearing needle can be extended or retracted within the cylindrical pen tip to a very small degree only. As a result, it is not possible to completely clear the capillary passage of crystallized ink.

(2) Description of the prior art The most pertinent prior art reference is Morton (291,- 925) who uses a magnet to impose a downward thrust on the cleaning wire, so as to extend the cleaning wire beyond the pen tip. However, there is no magnetic means provided for automatically retracting the cleaning wire within the pen tip.

SUMMARY OF THE INVENTION According to the present invention, regulation of air admitted to the drafting pen ink reservoir may be effected by a spring pressurized stem, which extends in construction through the top of an ink reservoir contained within the pen barrel. Simultaneously, this stem serves to impel a downward thrust to a cleaning wire to thereby provide a fast and complete cleaning of the ink passageway or scribing channel in the pen tip. Both venting of the ink reservoir and cleaning of the ink passageway may 3,535,048 Patented Oct. 20, 1970 be controlled by hand manipulation of a stem connected knob.

A permanent magnet located in the ink reservoir between the valve stem and cleaning wire or an upward extension of the cleaning wire serves to maintain a longitudinal connection between said stem and cleaning wire, whereby the cleaning wire follows the movements of the stem. This magnetic connection is ended if a manual longitudinally upward force is applied to valve stem. Then, the cleaning wire is brought to a stop in its maximum upward position in the ink reservoir as the upward force or tipping of the pen thus exceeds the magnetic attraction between the stem and cleaning wire.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. l is an enlarged vertical sectional view of the writing nib of a stylographic drafting pen according to the invention showing a magnet positioned between a valve stern and cleaning wire extending beyond the pen tip with the cleaning wire protruding;

FIG. 2 is an enlarged vertical sectional view of the writing nib according to FIG. l, with the cleaning wire over the distance A receded to its rest position within the pen tip;

FIG. 3 is an enlarged vertical sectional view of the writing nib according to FIGS. 1 and 2, with the cleaning wire upwardly removed over the distance B from its rest position by means of the magnet;

FIG. 4 is an enlarged fragmentary vertical sectional view of a modified writing nib with an ink chamber on top of the ink capillary passageway;

FIG. 5 is an enlarged sectional view of the writing nib according to FIGS. 1, 2, and 3 with the bottom part of the valve stem acting as a magnet armature;

FIG. 6 is an enlarged vertical sectional view of the writing nib according to FIGS. l, 2, 3, and 5 with a modified magnet construction;

FIG. 7 is a top plan of the -writing nib, according to FIG. l; and

FIG. 8 is a schematic view of the magnet system, according to FIGS. l, 2, and 3 with the armature separated from the magnet.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Pen 10 comprised barrel 12 (illustrated in phantom) and the writing nib 16 with the attached pen tip 18. Cleaning wire 20 is attached to permanent magnet 130 and the vent stem 74 with the armature 132 attached to its bottom end is connected to a stem knob (not illustrated) to manually reciprocate cleaning wire 20 in longitudinal directions.

In FIG. 1 the cleaning wire 20` is by means of the manually displaceable vent stem 74 forced downward to its lowest position with its bottom end 68 having extended over the distance A beyond the rest -position indicated in FIG. 2. Upward movement of cleaning wire 20 from the lowest FIG. 1 position to the FIG. 2 rest position is also achieved by means of the vent stem 74 displaced in an upward direction, due to the attraction force between magnet and armature 132. The forces of restriction on cleaning wire 20 in the ink passageway 84 are by far exceeded by the magnetic attraction force. Also, after a long period of non-usage of the drafting pen, passageway 84 may be completely clogged with dried crystallized ink. The magnetic forces are suiiicient, also, to pull cleaning wire 60 through clogged passageway 84.

Also, the top position of the cleaning wire 20 with this wire retracted over the distance B as illustrated in FIG. 3 removed from the rest position of FIG. 2 is made possible by means of the vent stem 74 in combination with the magnet system 130-132. If, however, magnet 130 is upwardly brought to rest against lock pin 106, as illustrated in FIG. 8 and upward force applied to stern 74 or a downward force applied on the magnet 130 via the writing nib and lock pin 106 which force exceeds magnetic attraction forces between magnet 130 and armature 132, armature 132 will be disconnected from the magnet.

This disconnection between stem 74 and cleaning wire 20 makes it possible to remove the writing nib 16 from the holder 12 for filling purposes with the thin cleaning wire 20, which easily can be damaged, remaining within the protective surroundings of passageway 84 and writing nib 16.

In FIG. 4 modified ink chamber 104 is shown, whereby cleaning lwire 20 by being upwardly moved over the distance B from its rest position with the aid of the vent stem 74, magnet 130 and armature 132 is brought into chamber 104.

In FIG. 5 the vent stem 74 being of steel or other suitable metal, also serves as the armature 132.

In FIG. 6 the magnet 130' has an axial recess 134 in its top, in which recess the underpart 136 of the armature 132' slidably lits. A temporary vacuum is created between underpart 136 and magnet 130. This vacuum produces a great attractive force between underpart 136 and magnet 130 which exceeds that of the magnet system. Thus, an extra safeguard against separation is achieved.

Since writing nib 16 is part of the ink reservoir of the drafting pen and the magnet system is located in the ink reservoir, the longitudinal position of the magnet system within the reservoir can be varied readily, as cleaning 'wire 20 is reciprocated between the positions indicated in FIGS. 1, 2, and 3.

Iclaim:

1. A self-cleaning writing pen comprising:

(A) a holder encompassing an ink reservoir;

(B) a pen tip having a top end communicant with said reservoir and an ink passage interconnecting said top and tip of said writing end;

(C) a cleaning 'wire extending from said reservoir into -said passage;

(D) a metallic weight secured to the end of said cleaning wire within said reservoir; and

(E) a reciprocable metallic valve stem being magnetically attracted to said weight and extending through said reservoir and said top end to engage said weight, the magnetic attraction between stem and weight being such that longitudinal retraction of said stern from said writing end, longitudinally lifts said weight and reciprocates said cleaning wire within said passage.

2. A self-cleaning writing pen as in claim 1, said cleaning wire extends beyond said writing end, is secured to said weight above said passage within said top end and is retractable inwardly of said passage, as said weight is lifted from said seat.

3. A self-cleaning writing pen as in claim 2, said passage including a widened portion adjacent said top end and offset with respect to said cleaning wire.

4. A writing pen as in claim 3, said magnetic attraction between weight and stem is suicient to lift said weight and cleaning wire as said stem is retracted longitudinally, despite drying of ink Within said passage.

5. A writing instrument as in claim 2, including:

(F) lock means extending inwardly of Said top end above said weight, as a limit to the longitudinal movement of said weight within said reservoir.

References Cited UNITED STATES PATENTS 291,925 1/1884 Morton 401-259 2,891,512 6/1959 lKovacs 401-258 X 3,247,828 4/1966 Basham 401-260 X FOREIGN PATENTS 831,961 2/1952 Germany.

LAWRENCE CHARLES, Primary Examiner 

